A Dramatic Classroom Demonstration of Limiting Reagent Using the Vinegar and Sodium Hydrogen Carbonate ReactionRomklao Artdej and Tienthong ThongpanchangThis demonstration, appropriate for high school chemistry level and recommended for a large classroom presentation, is designed to illustrate the concept of limiting reagent via a series of experiments in which increasing amounts of sodium bicarbonate are added to a fixed amount of vinegar is fixed until the volume of carbon dioxide generated remains constant. Artdej, Romklao; Thongpanchang, Tienthong. J. Chem. Educ.2008, 85, 1382.

Determination of the Formula of a Hydrate: A Greener AlternativeMarc A. Klingshirn, Allison F. Wyatt, Robert M. Hanson, and Gary O. SpessardThis article describes how the principles of green chemistry were applied to a first-semester, general chemistry courses, specifically in relation to the determination of the formula of a copper hydrate salt that changes color when dehydrated and is easily rehydrated with steam.Klingshirn, Marc A.; Wyatt, Allison F.; Hanson, Robert M.; Spessard, Gary O. J. Chem. Educ.2008, 85, 819.

Gravimetric Analysis |

Green Chemistry |

Solids |

Stoichiometry

A Simple Penny AnalysisNicholas C. Thomas and Stephen FaulkDescribes a simple procedure for determining the zinc composition of U.S. pennies in which the penny zinc core is dissolved in acid and the evolved hydrogen gas is collected by water displacement.Thomas, Nicholas C.; Faulk, Stephen. J. Chem. Educ.2008, 85, 817.

Yet Another Variation on the Electrolysis of Water at Iron NailsMark T. Stauffer and Justin P. FoxDescribes a variation on the electrolysis of water with iron nails in which a sharp contrast in the colors produced effectively demonstrates electrolysis and the diffusion of oxidized and reduced species from the electrodes.Stauffer, Mark T.; Fox, Justin P. J. Chem. Educ.2008, 85, 523.

Acids / Bases |

Electrochemistry |

Oxidation / Reduction |

Stoichiometry |

Water / Water Chemistry |

Electrolytic / Galvanic Cells / Potentials

NetorialsRebecca Ottosen, John Todd, Rachel Bain, Mike Miller, Liana Lamont, Mithra Biekmohamadi, and David B. ShawNetorials is a collection of about 30 online tutorials on general chemistry topics designed as a supplement for high school or college introductory courses. Each Netorial contains several pages of interactive instruction that includes animated mouse-overs, questions for students to answer, and manipulable molecular structures.Ottosen, Rebecca; Todd, John; Bain, Rachel; Miller, Mike; Lamont. Liana; Biekmohamadi, Mithra; Shaw, David B. J. Chem. Educ.2008, 85, 463.

Acids / Bases |

Electrochemistry |

Reactions |

VSEPR Theory |

Stoichiometry

Connecting Solubility, Equilibrium, and Periodicity in a Green, Inquiry Experiment for the General Chemistry LaboratoryKristen L. Cacciatore, Jose Amado, Jason J. Evans, and Hannah SevianPresents a novel first-year chemistry experiment that asks students to replicate procedures described in sample lab reports that lack essential information. This structure is designed to promote students' experimental design and data analysis skills as well as their understanding of the importance and essential qualities of written and verbal communication between scientists.Cacciatore, Kristen L.; Amado, Jose; Evans, Jason J.; Sevian, Hannah. J. Chem. Educ.2008, 85, 251.

Equilibrium |

Green Chemistry |

Periodicity / Periodic Table |

Solutions / Solvents |

Stoichiometry |

Titration / Volumetric Analysis

The Role of Water Chemistry in Marine Aquarium Design: A Model System for a General Chemistry ClassJeffrey J. Keaffaber, Ramiro Palma, and Kathryn R. WilliamsWater chemistry is central to aquarium design, and it provides many potential applications for discussion in undergraduate chemistry and engineering courses. This article uses a hypothetical tank to house ocean sunfish as a model to show students the calculations and other considerations that are needed when designing a marine aquarium.Keaffaber, Jeffrey J.; Palma, Ramiro; Williams, Kathryn R. J. Chem. Educ.2008, 85, 225.

Concept Maps for General Chemistry Boyd L. EarlTwo concept maps have been developed to represent the organization of the material in a first-semester general chemistry course. By providing these maps to students and referring to them in class, it is hoped that the instructor can assist students in maintaining a grasp of the "big picture" during the progress of the course.Earl, Boyd L. J. Chem. Educ.2007, 84, 1788.

Thermochemical Analysis of Neutralization Reactions: An Introductory Discovery ExperimentKenneth V. Mills and Louise W. GuilmetteDescribes a guided-inquiry laboratory pedagogy in which students discover chemical concepts in the lab and the instructor uses their pooled data to guide the lecture portion of the course. This method is illustrated by an experiment that reinforces students' understanding of stoichiometry and allows them to discover neutralization reactions and thermochemistry.Mills, Kenneth V.; Guilmette, Louise W. J. Chem. Educ.2007, 84, 326.

Job's Analysis of the Range of the "Dalton Syringe Rocket"Natalie Barto, Brandon Henrie, and Ed VitzAn apparatus for safely igniting fuel gas/oxygen mixtures in a syringe and measuring the distance that the syringe is propelled is presented. The distance (range) is analyzed by the method of continuous variation (Job's Method) to determine the stoichiometry of the reaction.Barto, Natalie; Henrie, Brandon; Vitz, Ed. J. Chem. Educ.2006, 83, 1505.

Gases |

Oxidation / Reduction |

Thermodynamics |

Stoichiometry

A Laboratory Experiment Using Molecular Models for an Introductory Chemistry ClassShahrokh GhaffariPresents a new approach to using molecular models in teaching general chemistry concepts. Students construct molecular models and use them to balance simple chemical equations, demonstrate the law of conservation of mass, and discover the relationship between the mole and molecules and atoms.Ghaffari, Shahrokh. J. Chem. Educ.2006, 83, 1182.

Stoichiometry of Calcium MedicinesGabriel PintoCalcium supplements provide an excellent context in which to review most of the core content of general chemistry, namely, stoichiometry, concentration units, hydration of salts, inorganic and organic salts, physiological importance of elements, resonance in ions, geometry of polyatomic ions, and isomerism.Pinto, Gabriel. J. Chem. Educ.2005, 82, 1509.

Stoichiometry |

Applications of Chemistry |

Drugs / Pharmaceuticals |

Medicinal Chemistry

Assessing the Effect of Web-Based Learning Tools on Student Understanding of Stoichiometry Using Knowledge Space TheoryRamesh D. Arasasingham, Mare Taagepera, Frank Potter, Ingrid Martorell, and Stacy LonjersThis paper reports a comparative study using knowledge space theory (KST) to assess the impact of a Web-based instructional software program on students' understanding of the concept of stoichiometry. The software program called Mastering Chemistry Web (MCWeb) allows students to practice problems that emphasize the development of molecular-level conceptualization and visualization, analytical reasoning, and proportional reasoning, as well as learning to recognize and relate different representations in chemistry. The experimental design compared students in two sections taught by the same instructor. One section used the MCWeb instructional software as homework (MCWeb group) while the other section used text-based homework (non-MCWeb group, control). Arasasingham, Ramesh D.; Taagepera, Mare; Potter, Frank; Martorell, Ingrid; Lonjers, Stacy. J. Chem. Educ.2005, 82, 1251.

Stoichiometry |

Student-Centered Learning

Mass Relationships in a Chemical Reaction: Incorporating Additional Graphing Exercises into the Introductory Chemistry LaboratoryStephen DeMeoThe purpose of this article is to increase student involvement with graph construction specifically in the context of introductory laboratory activities that involve mass relationships between reacting substances and products. In this regard, five massmass plots derived from a synthesis of a binary compound from its elements are presented as well as a set of questions to focus learners on the significance of each plot. The benefit of providing learners with these types of graphing activities include the use of higher-order cognitive processes as well as the elucidation of fundamental chemical knowledge such as the law of the conservation of mass, the law of constant composition, limiting and excess reactants, and empirical formula.DeMeo, Stephen. J. Chem. Educ.2005, 82, 1219.

Stoichiometry |

Oxidation / Reduction |

Reactions |

Quantitative Analysis

Cross-Proportions: A Conceptual Method for Developing Quantitative Problem-Solving SkillsElzbieta Cook and Robert L. CookThis paper focuses attention on the cross-proportion (C-P) method of mathematical problem solving, which was once widely used in chemical calculations. We propose that this method regain currency as an alternative to the dimensional analysis (DA) method, particularly in lower-level chemistry courses. In recent years, the DA method has emerged as the only problem solving mechanism offered to high-school and general chemistry students in contemporary textbooks, replacing more conceptual methods, C-P included. Cook, Elzbieta; Cook, Robert L. J. Chem. Educ.2005, 82, 1187.

Learning Theories |

Stoichiometry |

Chemometrics |

Student-Centered Learning

Amino Acid Complementarity: A Biochemical Exemplar of Stoichiometry for General and Health Sciences ChemistryEd VitzCalculations demonstrating amino acid complementarity are presented as an interesting application of stoichiometry. Food proteins are said to have complementary amino acids when the proteins combine to provide amino acids in the proper stoichiometric ratios to synthesize human protein. Implications for vegetarian diet, efficiency of food production, and diet adaptations in various cultures are explored briefly. Vitz, Ed. J. Chem. Educ.2005, 82, 1013.

Amino Acids |

Proteins / Peptides |

Stoichiometry |

Food Science

Analysis of OxiClean: An Interesting Comparison of Percarbonate Stain RemoversJeffrey D. Bracken and David TietzSeveral different brands of oxygen-based multipurpose stain removers consist of simple mixtures of sodium percarbonate and sodium carbonate. A small sample of each brand of stain remover is decomposed and then analyzed. The observed difference in mass allows students to accurately determine the percentages of each component of the stain remover. A back-titration experiment and a precipitation reaction are performed to confirm the complete decomposition of the original mixture.Bracken, Jeffrey D.; Tietz, David. J. Chem. Educ.2005, 82, 762.

Stoichiometry |

Consumer Chemistry

Procedure for Decomposing a Redox Reaction into Half-ReactionsIlie Fishtik and Ladislav H. BerkaThe principle of stoichiometric uniqueness provides a simple algorithm to check whether a simple redox reaction may be uniquely decomposed into half-reactions in a single way. For complex redox reactions the approach permits a complete enumeration of a finite and unique number of ways a redox reaction may be decomposed into half-reactions. Several examples are given. Fishtik, Ilie; Berka, Ladislav H. J. Chem. Educ.2005, 82, 553.

Stoichiometry |

Equilibrium |

Electrochemistry |

Oxidation / Reduction |

Reactions |

Thermodynamics

Evaluating Students' Conceptual Understanding of Balanced Equations and Stoichiometric Ratios Using a Particulate DrawingMichael J. SangerA total of 156 students were asked to provide free-response balanced chemical equations for a classic multiple-choice particulate-drawing question first used by Nurrenbern and Pickering. The balanced equations and the number of students providing each equation are reported in this study. The most common student errors included a confusion between the concepts of subscripts and coefficients and including unreacted chemical species in the equation. Sanger, Michael J. J. Chem. Educ.2005, 82, 131.

Stoichiometry |

Kinetic-Molecular Theory

Empirical Formulas and the Solid State: A ProposalWilliam B. JensenThis brief article calls attention to the failure of most introductory textbooks to point out explicitly the fact that nonmolecular solids do not have molecular formulas and suggests some practical remedies for improving textbook coverage of this subject. The inadequacies of the terms "empirical formula" and "molecular formula" are also discussed, and the terms "relative compositional formula" and "absolute compositional formula" are proposed as more appropriate alternatives. Jensen, William B. J. Chem. Educ.2004, 81, 1772.

Solid State Chemistry |

Solids |

Stoichiometry |

Nomenclature / Units / Symbols

Using Knowledge Space Theory To Assess Student Understanding of StoichiometryRamesh D. Arasasingham, Mare Taagepera, Frank Potter, and Stacy LonjersUsing the concept of stoichiometry we examined the ability of beginning college chemistry students to make connections among the molecular, symbolic, and graphical representations of chemical phenomena, as well as to conceptualize, visualize, and solve numerical problems. Students took a test designed to follow conceptual development; we then analyzed student responses and the connectivities of their responses, or the cognitive organization of the material or thinking patterns, applying knowledge space theory (KST). The results reveal that the students' logical frameworks of conceptual understanding were very weak and lacked an integrated understanding of some of the fundamental aspects of chemical reactivity. Arasasingham, Ramesh D.; Taagepera, Mare; Potter, Frank; Lonjers, Stacy. J. Chem. Educ.2004, 81, 1517.

Learning Theories |

Stoichiometry |

Constructivism

The Origin of the Mole ConceptWilliam B. JensenIn response to a reader query, the column traces the origins of the mole concept in chemistry. Jensen, William B. J. Chem. Educ.2004, 81, 1409.

The Decomposition of Zinc Carbonate: Using Stoichiometry To Choose between Chemical FormulasStephen DeMeoTo determine which formula corresponds to a bottle labeled "zinc carbonate", students perform qualitative tests on three of zinc carbonate's decomposition products: zinc oxide, carbon dioxide, and water. Next students make quantitative measurements to find molar ratios and compare them with the coefficients of the balanced chemical equations. This allows the correct formula of zinc carbonate to be deduced. DeMeo, Stephen. J. Chem. Educ.2004, 81, 119.

Gases |

Stoichiometry |

Quantitative Analysis

The Origin of Stoichiometry ProblemsWilliam B. JensenIn response to a reader query, the column discusses the question of when quantitative stoichiometry problems first began to appear in introductory textbooks, and especially the role of the American chemist, Josiah Parsons Cooke, in this process. Jensen, William B. J. Chem. Educ.2003, 80, 1248.

Determination of the Empirical Formula of a Copper Oxide Salt Using Two Different MethodsMichael J. Sanger and Kimberly GeerConverting copper oxide into copper metal using two different methods: reduction of copper oxide to copper metal using methane gas, and reduction of copper oxide to copper metal using aluminum in aqueous solution; the results are used to determine the empirical formula of copper oxide.Sanger, Michael J.; Geer, Kimberly. J. Chem. Educ.2002, 79, 994.

How to Say How Much: Amounts and StoichiometryAddison AultPictorial representation of the ways by which chemists describe an amount of material, and a systematic way to create a visual representation or "map" for solving stoichiometry problems.Ault, Addison. J. Chem. Educ.2001, 78, 1347.

Metal Complexes of Trifluoropentanedione. An Experiment for the General Chemistry LaboratoryRobert C. Sadoski, David Shipp, and Bill DurhamInvestigation of the transition-metal complexes produced by the reactions of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), and Cu(II) with 1,1,1-trifluoro-2,4-pentanedione; mass spectroscopy is used to determine the stoichiometry of the reaction products. Sadoski, Robert C.; Shipp, David; Durham, Bill. J. Chem. Educ.2001, 78, 665.

Coordination Compounds |

Synthesis |

Mass Spectrometry |

Transition Elements |

Stoichiometry

Analysis of an Oxygen Bleach: A Redox Titration LabChristine L. Copper and Edward KoubekStudents balance the reaction of H2O2 and MnO4 in two different ways (one assuming that H2O2 is the oxygen source and a second assuming that MnO4 is the oxygen source), determine which of these balanced equations has the correct stoichiometry by titrating a standard H2O2 solution with KMnO4, and use the correct balanced equation to determine the mass percent of H2O2 in a commercially available bleach solution. Copper, Christine L.; Koubek, Edward. J. Chem. Educ.2001, 78, 652.

Quantitative Analysis |

Oxidation / Reduction |

Stoichiometry |

Titration / Volumetric Analysis |

Consumer Chemistry

Using History to Teach Scientific Method: The Role of ErrorsCarmen J. GiuntaThis paper lists five kinds of error with examples of each from the development of chemistry in the 18th and 19th centuries: erroneous theories (phlogiston), seeing a new phenomenon everywhere one seeks it (Lavoisier and the decomposition of water), theories erroneous in detail but nonetheless fruitful (Dalton's atomic theory), rejection of correct theories (Avogadro's hypothesis), and incoherent insights (J. A. R. Newlands' classification of the elements). Giunta, Carmen J. J. Chem. Educ.2001, 78, 623.

Nonmajor Courses |

Periodicity / Periodic Table |

Kinetic-Molecular Theory |

Stoichiometry

The Synthesis and Analysis of Copper(I) Iodide. A First-Year Laboratory ProjectLara A. Margolis, Richard W. Schaeffer, and Claude H. YoderThis project provides a convenient preparation of a compound whose identity will not be obvious to students. The analytical procedures illustrate the fundamentals of gravimetric analysis and some basic chemical and physical characteristics of the elements. The analytical data allow students to find the identity of the product by determining its empirical formula.Margolis, Lara A.; Schaeffer, Richard W.; Yoder, Claude H. J. Chem. Educ.2001, 78, 235.

When A + B B + AErling Antony, Lindsay Mitchell, and Lauren NettenstromMany acid-base chemistry demonstrations and laboratory manuals include the "baking soda volcano". Others use the formation of calcium carbonate from calcium hydroxide and carbon dioxide in human breath. This demonstration uses principles from both as well as stoichiometry to answer the question "Does the order of mixing of reagents make a difference?" Antony, Erling; Mitchell, Lindsay; Nettenstrom, Lauren. J. Chem. Educ.2000, 77, 1180.

Acids / Bases |

Stoichiometry |

Reactions

Paradoxes, Puzzles, and Pitfalls of Incomplete Combustion DemonstrationsEd VitzPaper is burned in a closed container containing sufficient oxygen to consume all the paper. Paradoxically, the flame expires while half of the paper remains. This demonstrates that thermodynamics or stoichiometry is insufficient to explain everyday chemical processes, and that kinetics is often necessary. The gases in the container are analyzed by GC before and after combustion, and the results are examined in detail. Vitz, Ed. J. Chem. Educ.2000, 77, 1011.

Gases |

Kinetics |

Stoichiometry

A Drop in the OceanDamon DiementeTeachers of high-school chemistry customarily use calculations done as in-class exercises or as demonstrations to impress their students with the enormity of Avogadro's number and the concomitant miniscularity of atoms and molecules. This article presents and works out one such calculation. Diemente, Damon. J. Chem. Educ.2000, 77, 1010.

The Use of Extent of Reaction in Introductory CoursesSebastian G. CanagaratnaThis article discusses the use of the extent of reaction as an alternative to the traditional approach to stoichiometry in first-year chemistry. The method focuses attention on the reaction as a whole rather than on pairs of reagents as in the traditional approach. The balanced equation is used as the unit of change. Canagaratna, Sebastian G. J. Chem. Educ.2000, 77, 52.

Preparation and Properties of an Aqueous FerrofluidPatricia Enzel, Nicholas B. Adelman, Katie J. Beckman, Dean J. Campbell, Arthur B. Ellis, and George C. LisenskyThis paper describes a simple synthesis of an aqueous-based ferrofluid that may be used in an introductory science or engineering laboratory. This paper also describes a method for repelling both oil- and water-based ferrofluid from solid surfaces that would otherwise be stained by the fluid. Finally, a demonstration of the interaction between ferrofluid and magnetic fields, in which ferrofluid is induced to leap upward by a stack of magnets, is described. Enzel, Patricia; Adelman, Nicholas B.; Beckman, Katie J.; Campbell, Dean J.; Ellis, Arthur B.; Lisensky, George C. J. Chem. Educ.1999, 76, 943.

Materials Science |

Magnetic Properties |

Nanotechnology |

Stoichiometry |

Colloids

Limiting Reactant. An Alternative AnalogyZoltn TthA concrete analogy involving students and the make-up of teams is proposed to better explain the identification of the limiting reactant in stoichiometric calculations. Tth, Zoltn. J. Chem. Educ.1999, 76, 934.

Stoichiometry

Pressure and StoichiometryCharles E. Roser and Catherine L. McCluskeyThis experiment determines the stoichiometry of the reaction of a carbonate or hydrogen carbonate and HCl by measuring the pressure of the CO2 produced using a Vernier pressure sensor, TI CBL interface, and a TI-82/83 graphing calculator. Various amounts of the carbonate are reacted with a constant amount of HCl. Roser, Charles E.; McCluskey, Catherine L. J. Chem. Educ.1999, 76, 638.

Stoichiometry |

Gases |

Laboratory Computing / Interfacing

Using Games To Teach Chemistry. 2. CHeMoVEr Board GameJeanne V. RussellA board game similar to Sorry or Parcheesi was developed. Students must answer chemistry questions correctly to move their game piece around the board. Card decks contain questions on balancing equations, identifying the types of equations, and predicting products from given reactants. Russell, Jeanne V. J. Chem. Educ.1999, 76, 487.

Stoichiometry |

Nomenclature / Units / Symbols

The Ammonia Smoke Fountain: An Interesting Thermodynamic AdventureM. Dale AlexanderThe ammonia smoke fountain demonstration utilizes a modification of the apparatus used in the standard ammonia fountain. The modification allows for the introduction of hydrogen chloride gas into a flask of ammonia rather than water. The flow rate of hydrogen chloride gas into the flask in the smoke fountain is not constant, but periodic; that is, the smoke puffs from the end of the tube. This unexpected behavior elicits an interesting thermodynamic explanation.Alexander, M. Dale. J. Chem. Educ.1999, 76, 210.

Acids / Bases |

Gases |

Thermodynamics |

Reactions |

Stoichiometry |

Precipitation / Solubility

Replace Double ReplacementR. Bruce MartinReactions described as double replacements in high school texts are poorly described by this designation. The driving force for such reactions is precipitation of a solid derived from ions in solution or the production of water in acid-base reactions. Martin, R. Bruce. J. Chem. Educ.1999, 76, 133.

Stoichiometry |

Reactions |

Precipitation / Solubility

Amounts Tables as a Diagnostic Tool for Flawed Stoichiometric ReasoningJohn Olmsted IIIAmounts tables can be used to organize the data and reasoning involved in limiting-reagent problems. In this context, amounts tables can provide useful diagnostic information about students' abilities to reason stoichiometrically. Olmsted, John A., III. J. Chem. Educ.1999, 76, 52.

Learning Theories |

Stoichiometry

CHEMiCALC (4000161) and CHEMiCALC Personal Tutor (4001108), Version 4.0 (by O. Bertrand Ramsay)Scott White and George BodnerCHEMiCALC is a thoughtfully designed software package developed for use by high school and general chemistry students, who will benefit from the personal tutor mode that helps to guide them through unit conversion, empirical formula, molecular weight, reaction stoichiometry, and solution stoichiometry calculations.White, Scott; Bodner, George M. J. Chem. Educ.1999, 76, 34.

Percent Composition and Empirical Formula - A New ViewGeorge L. GilbertA new method of obtaining the empirical formula for a compound from its percent composition is proposed. The method involves the determination of a minimum molar mass for the compound based on the percentage of each element, obtaining the lowest common molar mass and using this data to calculate the integer values used in writing the empirical formula. Gilbert, George L. J. Chem. Educ.1998, 75, 851.

Atomic Properties / Structure |

Stoichiometry |

Chemometrics

A Closer Look at the Addition of Equations and ReactionsDamon DiementeChemists occasionally find it convenient or even necessary to express an overall reaction as the sum of two or more component reactions. A close examination, however, reveals that the resemblance between chemical algebraic equations is entirely superficial, and that the real meaning of addition in chemical equations is subtle and varies from case to case. In high-school courses, students are likely to encounter the addition of equations in thermochemistry, in electrochemistry, and in kinetics. Diemente, Damon. J. Chem. Educ.1998, 75, 319.

Redox Balancing without PuzzlingMarten J. ten HoorOnce it has been established by experiment that the given reactants can indeed be converted into the given products, chemistry has done its job. Balancing the equation of the reaction is a matter of mathematics only. ten Hoor, Marten J. J. Chem. Educ.1997, 74, 1367.

Stoichiometry |

Oxidation / Reduction

A New and General Method for Balancing Chemical Equations by InspectionsChunshi GuoAny chemical equation, no matter how complicated, can be balanced by inspection. In fact, inspection is often the quickest and easiest way to balance complex equation. The method described here involves the use of "linked sets". It does not require the use of oxidation numbers of the splitting of equations into "half reactions". It can be used to balance all kinds of chemical equations, including ionic equations.Guo, Chunshi. J. Chem. Educ.1997, 74, 1365.

Stoichiometry

Balancing Chemical Equations by InspectionZoltán TóthThe paper shows that the balancing chemical equations by inspection is not a trial-and-error process, because a systematic procedure for the balancing simple and more complicated chemical equations without oxidation numbers or equations with several unknowns can be suggested. The proposed method is suitable for balancing all the chemical equations, including ionic equations, which have single unique solution. Toth, Zoltan. J. Chem. Educ.1997, 74, 1363.

Stoichiometry

On Balancing Chemical Equations: Past and PresentWilliam C. HerndonThe main purposes of this paper are to give a listing of selected papers on balancing chemical equations that may be useful to chemistry teachers and potential authors as background material, and to provide some comparisons of methods. The selection criteria for the references were deliberately broad, in order to include a wide variety of topics and seminal historical citations, and the references are annotated to increase their usefulness.Herndon, William C. J. Chem. Educ.1997, 74, 1359.

Stoichiometry

Formation and Dimerization of NO2 A General Chemistry ExperimentApril D. Hennis, C. Scott Highberger, and Serge Schreiner*A general chemistry experiment which illustrates Gay-Lussac's law of combining volumes. Students are able to determine the partial pressures and equilibrium constant for the formation and dimerization of NO2. The experiment readily provides students with data that can be manipulated with a common spreadsheet. Hennis, April D.; Highberger, C. Scott; Schreiner, Serge. J. Chem. Educ.1997, 74, 1340.

Gases |

Equilibrium |

Quantitative Analysis |

Stoichiometry

How Big Is the Balloon? Stoichiometry Using Baking Soda and VinegarStudents discover the concept of stoichiometry and limiting reactants in two ways: first by adding vinegar to a small quantity of baking soda until bubbles stop, and second by mixing a constant quantity of baking soda with increasing volumes of vinegar and collecting the carbon dioxide produced in balloons.J. Chem. Educ.1997, 74, 1328A.

An Analysis of the Algebraic Method for Balancing Chemical ReactionsJohn A. OlsonA new aspect of this treatment is the mathematical formulation of a third condition involving a balance between oxidation and reduction. The treatment begins with the three general conditions that a balanced chemical reaction must satisfy. These conditions are then expressed in mathematical form that enables the stoichiometric coefficients to be determined.Olson, John A. . J. Chem. Educ.1997, 74, 538.

Oxidation / Reduction |

Stoichiometry

Stoogiometry: A Cognitive Approach to Teaching StoichiometryCarla R. KriegerMoe's Mall is a locational device designed to be used by learners as a simple algorithm for solving mole-based exercises efficiently and accurately. The mall functions as a map for setting up solutions to mole-based exercises using dimensional analysis. It clears the cognitive decks of students' easily overburdened short-term memory space, allowing them to focus on the versatility of the mole, rather than stepwise solutions to meaningless exercises. Krieger, Carla R. J. Chem. Educ.1997, 74, 306.

How Do I Balance Thee? ... Let Me Count the Ways!Lawrence A. FergusonThe author suggests that this would be a good equation for students to try to balance by trial and error because it has two different sets of coefficients that are not multiples of each other. Ferguson, Lawrence A. J. Chem. Educ.1996, 73, 1129.

Stoichiometry

An Approach to Reaction Thermodynamics through Enthalpies, Entropies, and Free Energies of AtomizationJames N. Spencer, Richard S. Moog, and Ronald J. GillespieAn alternative to the conventional method of calculating enthalpies of reaction is presented, using enthalpies of atomization in place of enthalpies of formation. This allows the student to see directly that the reaction enthalpies are determined by the difference in bond strengths in the reactants and products.James N. Spencer, Richard S. Moog, and Ronald J. Gillespie. J. Chem. Educ.1996, 73, 631.

What's a Mole for?Sheryl DominicA classroom competition for guessing the number of jelly beans in a jar of candy is used to help students understand the premise of the mole concept: counting particles by weighing. Dominic, Sheryl. J. Chem. Educ.1996, 73, 309.

Stoichiometry

Reinforcing Net Ionic Equation Writing: Second SemesterBetty J. WruckIt is important to actively illustrate that total and net ionic equation writing is a way of learning and expressing an enormous amount of chemistry. There is a major problem with students retaining their ability to write net ionic equations in the second semester. We start this semester with a review and a special, long range assignment. Wruck, Betty J. J. Chem. Educ.1996, 73, 149.

Those Baffling SubscriptsArthur W. Friedel and David P. MaloneyStudy of the difficulties students have in interpreting subscripts correctly and distinguishing atoms from molecules when answering questions and solving problems.Friedel, Arthur W.; Maloney, David P. J. Chem. Educ.1995, 72, 899.

A Graphical Representation of Limiting ReactantPhillips, J. C.The concept of limiting reactant may be conveniently illustrated by a graphical representation method that is based on a "minimum slope".Phillips, J. C. J. Chem. Educ.1994, 71, 1048.

Unknown identification by simple stoichiometryMcCullough, ThomasA simple experiment in which the student can determine the identity of a soluble carbonate salt using one straightforward reaction and gravimetric analysis.McCullough, Thomas J. Chem. Educ.1993, 70, 592.

A mole of M&M's Merlo, Carmela; Turner, Kathleen E.Engaging students by asking the question: How thick would the layer of M&M candies be if we covered the continental United States with a mole of these candies? Compare this to a mole of water.Merlo, Carmela; Turner, Kathleen E. J. Chem. Educ.1993, 70, 453.

Stoichiometry |

Chemometrics

AnswerSheetsCornelius, RichardReview of a spreadsheet-like program that includes modules on significant figures, conversions, stoichiometry, and VSEPR structures.Cornelius, Richard J. Chem. Educ.1993, 70, 387.

Measuring Avogadro's number on the overhead projector Solomon, Sally; Hur, ChinhyuA Petri dish filled with water and stearic acid dissolved in petroleum ether upon an overhead projector can be used to introduce the topic of Avogadro's number.Solomon, Sally; Hur, Chinhyu J. Chem. Educ.1993, 70, 252.

Gas chamber stoichiometry Hunter, Norman W.; Wilkins, Curtis C.; Pearson, Earl F.Most students know that HCN is used in gas chambers, they may not know however that HCN is produced in the burning of carpets, draperies, clothing and other textiles made of polyacrylonitrile.Hunter, Norman W.; Wilkins, Curtis C.; Pearson, Earl F. J. Chem. Educ.1992, 69, 389.

Balancing a chemical equation: What does it mean?Filgueiras, Carlos AStudents were puzzled by the idea that one chemical equation could be balanced in several different ways. This led to a fruitful discussion on how exact a science chemistry really is.Filgueiras, Carlos A J. Chem. Educ.1992, 69, 276.

A mole mnemonicBrown, Bernard S.This article features a chart that provides a fun mnemonic offered to help students struggling with the concept of the mole by making ideas more concrete.Brown, Bernard S. J. Chem. Educ.1991, 68, 1039.

Stoichiometry

Chemical equations are actually matrix equationsAlberty, Robert A.Chemists tend to think that chemical equations are unique to chemistry and they are not used to thinking of chemical equations as the mathematical equations they in fact are. The objective of this paper is to illustrate the mathematical significance of chemical equations.Alberty, Robert A. J. Chem. Educ.1991, 68, 984.

Stoichiometry |

Chemometrics

A BASIC program for computing reactant combinations from approximate elemental analysis dataSenthilkumar, Udayampalayam P.; Vijayalakshmi, Rajagopalan; Jeyaraman, Ramasubbu129. A computer program has been developed for determining the number of moles of reactants participating in a reaction in addition to calculating the molecular formula for the analytical data.Senthilkumar, Udayampalayam P.; Vijayalakshmi, Rajagopalan; Jeyaraman, Ramasubbu J. Chem. Educ.1991, 68, 773.

Copper dissolution in nitric acid Stairs, Robert A.Previous correspondence on the stoichiometry of the dissolution of copper in nitric acid is confused as a result of the attempt to write a single equation.Stairs, Robert A. J. Chem. Educ.1990, 67, 184.

A proposition about the quantity of which mole is the SI unitRocha-Filho, Romeu C.In this note, after a brief review of the evolution of the meaning of the term mole and a discussion of intrinsic properties of matter, it is proposed that the quantity measured using the SI base unit mole is numerousness, an intrinsic property of samples of matter.Rocha-Filho, Romeu C. J. Chem. Educ.1990, 67, 139.

Stoichiometry

Hot stellar molesMartin, John S.To reinforce elemental concepts of chemistry, it helps to see how they work under unusual conditions.Martin, John S. J. Chem. Educ.1990, 67, 138.

A stoichiometric journeyMolle, BrianA story to help students overcome some of the difficulties they encounter in stoichiometry calculations.Molle, Brian J. Chem. Educ.1989, 66, 561.

Stoichiometry |

Chemometrics

Overall chemical equationsGil, Victor M. S.An equation sum can be used safely by itself in stoichiometric and equilibrium calculations only if the intermediates produced in separate reactions are at low steady-state concentrations and if there are no other equilibria involving those species.Gil, Victor M. S. J. Chem. Educ.1989, 66, 324.

Stoichiometry |

Equilibrium

Moles, pennies, and nickelsMyers. Thomas R.Students frequently have difficulty with the mole concept initially because atoms and molecules are involved and these are invisible.Myers. Thomas R. J. Chem. Educ.1989, 66, 249.

Stoichiometry

A question of basic chemical literacy? Missen, Ronald W.; Smith, William R.The ability to read and write clearly in chemical-equation terms is not as well developed as it should be. The purpose of this "Provocative Opinion" is to draw attention to this problem, and to suggest specific remedies for its solution.Missen, Ronald W.; Smith, William R. J. Chem. Educ.1989, 66, 217.

Stoichiometry

Teaching stoichiometry: A two cycle approach Poole, Richard L.It is the intent of this article to describe and illustrate a tandem approach for the teaching of stoichiometry that the author developed.Poole, Richard L. J. Chem. Educ.1989, 66, 57.

Questions from a can of PepsiMitchell, TonyA can of Pepsi can be the starting point of countless chemistry questions that students can relate to. The author encourages other instructors to think about helping students understand chemistry as it relates to contemporary society.Mitchell, Tony J. Chem. Educ.1988, 65, 1070.

Consumer Chemistry |

Applications of Chemistry |

Stoichiometry |

Physical Properties |

Food Science |

Nutrition |

Gases |

Acids / Bases |

Metals

Teaching stoichiometry Figueira, Alvaro RochaStudents have a hard time with stoichiometry because it is often presented in a manner that is divorced from content and application.Figueira, Alvaro Rocha J. Chem. Educ.1988, 65, 1060.

An alternative to using the PV = nRT equation Desmarais, GeorgeThis author shares his application of the factor-label method to solving gas problems which involves using the ideal gas constant as the starting point in the relationship.Desmarais, George J. Chem. Educ.1988, 65, 392.

A multi-topic problem for general chemistry Burness, James H.A 'marathon' problem which requires specific knowledge in several areas while requiring that the student recognize how these areas are related.Burness, James H. J. Chem. Educ.1988, 65, 145.

An aqueous problem with an interesting solutionThomas, Nicholas C.Flow diagram outlining the steps to calculating the number of water molecules in one drop of water and the length of all these molecules stretched end to end.Thomas, Nicholas C. J. Chem. Educ.1987, 64, 611.

Mole fraction revisitedMancott, A.This problem requires the use of algebraic reasoning to derive and solve a fraction linear equation based on the concept of moles and conservation of moles.Mancott, A. J. Chem. Educ.1987, 64, 320.

Stoichiometry |

Chemometrics

Election results and reactions yieldsRocha-Filho, Romeu C.Reactions do not always proceed to products as expected from the stoichiometry; sometimes only a fraction of the reagents undergo reaction, while at other times, side products are formed due to competing reactions.Rocha-Filho, Romeu C. J. Chem. Educ.1987, 64, 248.

Stoichiometry

A new method to balance chemical equationsGarcia, ArcesioA simple method, applicable to any kind of reaction, that does not require the knowledge of oxidation numbers.Garcia, Arcesio J. Chem. Educ.1987, 64, 247.

Teaching stoichiometry Steiner, Richard P.This author targets some of the reasons behind why it is so difficult for beginning chemistry students to understand stoichiometry. He reveals that if taught correctly and effectively, a 7-year old can grasp the concepts of stoichiometry.Steiner, Richard P. J. Chem. Educ.1986, 63, 1048.

What can we do about Sue: A case study of competenceHerron, J. Dudley; Greenbowe, Thomas J.A case study of a "successful" student who is representative of other successful students that are not prepared to solve novel problems.Herron, J. Dudley; Greenbowe, Thomas J. J. Chem. Educ.1986, 63, 528.

Name that compound Mancott, A.These two problems require the use of algebraic reasoning and the application of the concepts of moles, atomic weights, and formulas-these are important facets of the general chemistry course.Mancott, A. J. Chem. Educ.1986, 63, 413.

Mathematics in the chemistry classroom. Part 2. Elementary entities play their partDierks, Werner; Weninger, Johann; Herron, J. DudleyOne of the problems that learners have to overcome when doing stoichiometry calculations is to learn how statements about elementary entities given by formulas and equations are related to statements about portions of substances as measured in the macroscopic world.Dierks, Werner; Weninger, Johann; Herron, J. Dudley J. Chem. Educ.1985, 62, 1021.

The mole: Questioning format can make a differenceLazonby, John N.; Morris, Jane E.; Waddington, David J.Study of 2,695 high school students that found that it is the piecing together of the individual steps involved in mole calculations that presents the main difficulty for students.Lazonby, John N.; Morris, Jane E.; Waddington, David J. J. Chem. Educ.1985, 62, 60.

Nomenclature / Units / Symbols |

Stoichiometry

A LAP on moles: Teaching an important conceptIhde, JohnThe objective of the Learning Activity Packet on moles include understanding the basic concept of the mole as a chemical unit, knowing the relationships between the mole and the atomic weights in the periodic table, and being able to solve basic conversion problems involving grams, moles, atoms, and molecules. [Debut]Ihde, John J. Chem. Educ.1985, 62, 58.

Composition of gas hydrates. New answers to an old problemCady, George H.The author provides a discussion on nonstoichiometric crystalline solids as they deserve attention in elementary chemistry courses because they are interesting and increasingly important. Laboratory activities are included.Cady, George H. J. Chem. Educ.1983, 60, 915.

Estimating energy outputs of fuelsBaird, N. ColinWhich is the best fuel in terms of heat energy output: coal, natural gas, fuel oil, hydrogen, or alcohol? It is possible to obtain a semi quantitative estimate of the heat generated by combustion of a fuel from the balanced chemical equation alone.Baird, N. Colin J. Chem. Educ.1983, 60, 356.

Reactions |

Green Chemistry |

Thermodynamics |

Alcohols |

Alkanes / Cycloalkanes |

Geochemistry |

Stoichiometry |

Quantitative Analysis

The liquid silver parade Perkins, RobertThe activity described in this note is useful in illustrating how small atoms are to students.Perkins, Robert J. Chem. Educ.1983, 60, 343.

Bad booze O'Connor, RodOne of the brain tinglers: What is the maximum volume of 95% ethanol that a 120lb student could consume to reach a potentially lethal dosage of alcohol? This tingler also helps students understand why it is important to have denatured alcohol in the lab.O'Connor, Rod J. Chem. Educ.1981, 58, 502.

Alcohols |

Toxicology |

Stoichiometry |

Applications of Chemistry

Pressure and the exploding beverage container Perkins, Robert R.The question in this article is an extension of exploding pop bottles to illustrate the balancing of a chemical equation, enthalpy, stoichiometry, and vapor pressure calculations, and the use of the Ideal Gas Equation. The question is aimed at the first-year level student.Perkins, Robert R. J. Chem. Educ.1981, 58, 363.

Stoichiometry |

Gases |

Thermodynamics |

Chemometrics

An experimental introduction to stoichiometry Webb, Michael J.A procedure for an experiment with the purpose: To show via experiment that the quantities of materials used in chemical reactions are related to balanced chemical equations.Webb, Michael J. J. Chem. Educ.1981, 58, 192.

Stoichiometry |

Reactions

An approximate determination of Avogadro's constantSzll, Thomas; Dennis, David; Jouas, Jean-Pierre; Wong, MabelAn experiment to determine a value for Avogadro's number by determining the relationship between the number of electrons flowing through an acidified solution of water and the number of moles of electrons which reduce hydrogen ions to produce hydrogen gas.Szll, Thomas; Dennis, David; Jouas, Jean-Pierre; Wong, Mabel J. Chem. Educ.1980, 57, 735.

A chemistry lesson at Three Mile IslandMammano, Nicholas J.Teaching principles of general chemistry through references made to the nuclear incident at Three Mile Island.Mammano, Nicholas J. J. Chem. Educ.1980, 57, 286.

Evolution of an experiment (from moles/I2 to gaseous CaCl2)Dauphinee, G. A.An experiment originally designed to illustrate a simple problem in solution stoichiometry has produced a stimulus to student recognition of some applications of descriptive chemistry.Dauphinee, G. A. J. Chem. Educ.1979, 56, 116.

The chemical equation. Part I: Simple reactionsKolb, DorisA chemical equation is often misunderstood by students as an "equation" that is used in chemistry. However, a more accurate description is that it is a concise statement describing a chemical reaction expressed in chemical symbolism.Kolb, Doris J. Chem. Educ.1978, 55, 184.

Cookbook dimensional analysisDeLorenzo, RonaldFrequently, teachers will hear, "...it looks easy when you do it..." when teaching dimensional analysis. This teacher advises others on a way to help students gain self-efficacy with this problem solving-strategy.DeLorenzo, Ronald J. Chem. Educ.1976, 53, 633.

An experiment for introductory college chemistry. How to establish a chemistry equationMasaguer, J. R.; Coto, M. Victoria; Casas, J. S.The stoichiometry of the reaction between potassium chromate and barium chloride in an aqueous state is determined by using the height of of the precipitate formed when different amounts of both solutions are mixed in a graduated cylinder.Masaguer, J. R.; Coto, M. Victoria; Casas, J. S. J. Chem. Educ.1975, 52, 387.

Chemical queries. Especially for introductory chemistry teachersYoung, J. A.; Malik, J. G.; Strong, Laurence E.(1) What evidence, understandable and acceptable to students, do most teachers cite to describe the transfer of charge from one electrode to another in the direct current electrolysis of an electrolyte solution? (2) What is a compound? - answer by Strong. (3) What is a molecule? - answer by Strong.Young, J. A.; Malik, J. G.; Strong, Laurence E. J. Chem. Educ.1970, 47, 523.

Avogadro's number from the volume of a monolayerMoynihan, Cornelius T.; Goldwhite, HaroldThis article comments on and makes suggestions regarding the conduct of and treatment of data in the popular experiment in which Avogadro's number is estimated from the volume of a monolayer on a water surface.Moynihan, Cornelius T.; Goldwhite, Harold J. Chem. Educ.1969, 46, 779.

An improved equivalent weight apparatusBrown, Oliver L.Presents an improved apparatus for the reaction of weighed samples of metals with hydrochloric acid and the measurement of the volume of hydrogen evolved.Brown, Oliver L. J. Chem. Educ.1969, 46, 617.

Laboratory Equipment / Apparatus |

Metals |

Laboratory Management |

Reactions |

Gases |

Stoichiometry

Thermochemistry of hypochlorite oxidationsBigelow, M. JeromeStudents mix various proportions of aqueous sodium hypochlorite and sodium sulfite and plot the change in temperature to determine the stoichiometry of the reaction.Bigelow, M. Jerome J. Chem. Educ.1969, 46, 378.

Calorimetry / Thermochemistry |

Oxidation / Reduction |

Aqueous Solution Chemistry |

Stoichiometry |

Thermodynamics |

Mechanisms of Reactions

Avogadro's number by four methodsSlabaugh, W. H.Describes a project by two general chemistry students to compare four methods for finding Avogadro's number; this article focusses on the electroplating method.Slabaugh, W. H. J. Chem. Educ.1969, 46, 40.

Chemical queries. Especially for introductory chemistry teachersYoung, J. A.; Malik, J. G.; Bolte, John(1) Is the mole a number or a weight? (2) Is there an easy way to locate a compound by volume and page in Beilstein? (3) What are the stages evident in a gas discharge tube as the pressure of the gas and the voltage are changed? - answer by BolteYoung, J. A.; Malik, J. G.; Bolte, John J. Chem. Educ.1968, 45, 718.

Stoichiometry |

Nomenclature / Units / Symbols |

Gases

From stoichiometry and rate law to mechanismEdwards, John O.; Greene, Edward F.; Ross, JohnExamines the rules used by chemists as guidelines in developing mechanisms from stoichiometric and rate law observations. Edwards, John O.; Greene, Edward F.; Ross, John J. Chem. Educ.1968, 45, 381.

Letter to the editorBacon, E. K.Examines values collected when using the production of copper sulfide to demonstrate the law of constant proportions.Bacon, E. K. J. Chem. Educ.1967, 44, 620.

Stoichiometry |

Synthesis

The stoichiometry of an oxidation-reduction reactionLatimer, George W., Jr.A short note on the titration of hydrazine sulfate with standard bromate in the presence of sodium molybdate that requires students to identify the products through the use of some elementary qualitative analysis.Latimer, George W., Jr. J. Chem. Educ.1967, 44, 537.

The relationship between Avogadro's Principle and the Law of Gay-LussacFeifer, NathanTeaching Avogadro's Principle as an explanation of the phenomena described by Gay-Lussac's Law gives the instructor an opportunity to stress some of the basic assumptions in chemistry and to highlight the logic implicit in Avogadro's reasoning.Feifer, Nathan J. Chem. Educ.1966, 43, 411.

Molecules versus molesGuggenheim, E. A.Now that the mass of molecules is known with great accuracy, there is nothing to be gained in continuing to use moles.Guggenheim, E. A. J. Chem. Educ.1966, 43, 250.

Stoichiometry of the reaction of bromine with phenolsLockwood, Karl L.The purpose of this investigation is to establish the stoichiometry for the reaction of a number of phenols with bromine, and to demonstrate the rapid and quantitative nature of the reaction of bromine with enols.Lockwood, Karl L. J. Chem. Educ.1965, 42, 482.

Determination of Avogadro's number by Perrin's lawSlabaugh, W. H.The experimental procedure for determining Avogadro's number by the Perrin method includes preparing a monodisperse colloid, ascertaining the mass of the particles, and making an accurate count of the number of particles at two points in the equilibrated colloid.Slabaugh, W. H. J. Chem. Educ.1965, 42, 471.

A molality-molarity paradox?Toby, SidneyThe author points out that there seems no obvious reason why molality could not equal molarity in a solution whose density is less than unity.Toby, Sidney J. Chem. Educ.1959, 36, 230.

Letters to the editorGaddis, Shirley W.Has not the time come to bring up for debate the question of the advisability of teaching the equivalent weight concept?Gaddis, Shirley W. J. Chem. Educ.1955, 32, 289.

Gram equivalent weightsMeldrum, William B.The purpose of this paper is to review briefly the subject of equivalent weights and the more directly applicable gram equivalents and to offer a general method by which they may be deduced from chemical equations.Meldrum, William B. J. Chem. Educ.1955, 32, 48.

Nomenclature / Units / Symbols |

Stoichiometry

Material balances and redox equationsBennett, George W.It is the purpose of this paper to remind teachers of a third method of balancing redox equations that does not depend on rule-of-thumb empiricism but relies on the conservation of matter.Bennett, George W. J. Chem. Educ.1954, 31, 324.

Stoichiometry |

Oxidation / Reduction |

Oxidation State

Otis Coe Johnson and redox equationsBennett, George W.It is the purpose of this paper to point out what is basic verity and what is empiricism in Johnson's method for balancing oxidation-reduction equations.Bennett, George W. J. Chem. Educ.1954, 31, 157.

Oxidation / Reduction |

Oxidation State |

Stoichiometry

Letters to the editorStanden, AnthonyHelping students to understand the experiment they have done is a difficult task; experiments that claim to "prove" physical laws or determine Avogadro's number compound this problem.Standen, Anthony J. Chem. Educ.1954, 31, 46.

Stoichiometry

LettersNair, C. N.A mathematical derivation demonstrating that masses of different elements equal to their atomic weights must contain the same number of atoms.Nair, C. N. J. Chem. Educ.1953, 30, 155.

Stoichiometry |

Atomic Properties / Structure

Recent history of the notion of a chemical speciesBulloff, Jack J.Quantum and nuclear chemistry have challenged the doctrine that chemical elements are homogeneous entities while studies of the structure and stoichiometry of solids invite a change in our ideas of definite proportions in chemical combinations.Bulloff, Jack J. J. Chem. Educ.1953, 30, 78.

Nuclear / Radiochemistry |

Isotopes |

Stoichiometry |

Solids

An experiment on the law of multiple proportionsSecrist, John H.It is suggested that the reduction of cuprous and cupric oxides serves as a satisfactory laboratory demonstration of the law of multiple proportions.Secrist, John H. J. Chem. Educ.1952, 29, 283.

Stoichiometry |

Oxidation / Reduction

On accenting observations in chemistryCampbell, J. A.A chemical equations is, for many a student, such a complete abstraction that he would be hard put to describe the actual observations that would be made in a process for which he was supplied the complete equation.Campbell, J. A. J. Chem. Educ.1951, 28, 634.

Reactions |

Stoichiometry |

Nomenclature / Units / Symbols

A common misunderstanding of Hess' lawDavis, Thomas. W.The statement, sometimes attributed to Hess, that "In any series of chemical or physical changes the total heat effect is independent of the path by which the system goes from its initial to its final state" is incorrect.Davis, Thomas. W. J. Chem. Educ.1951, 28, 584.

Stoichiometry |

Acids / Bases |

Aqueous Solution Chemistry |

Calorimetry / Thermochemistry

LettersSeeger, WalfriedCommentary on determining the combining weights of zinc or cadmium by dissolving them in HCl or aqua regia.Seeger, Walfried J. Chem. Educ.1951, 28, 397.